Running the vid in slow motion and found my first toughts right. At first the ship lost the complete last tailboom part incl. the intermediate gearbox and not only the T/R. A few seconds later parts of rotor blades disintegrated. For me a sign of a damaged M/R. And a damaged M/R is not the result of a "simple" T/R loss.
On this scenario a power cut will do nothing. The damaged M/R blades will result in heavy vibrations, an unbalance and may be in an uncontrollable helicopter. This unlucky guys were doomed. May be they have done it and tried an AR. But an increasing M/R RPM will rapidly increase the forces on the blades and a disintegration.
still dont know the difference between mi-17 and mi-8?
The best way to decide if seeing an older Mi-8 or the newer models (names are difficult, sometimes Mi-17 variants are decribed as Mi-8 MTV) is to look at the engine cowlings. On the newer variants with the more powerful engines the engines are much shorter than the old TW117 on the Mi-8. Therefore there is more distance between the front of the helicopter and the air inlets. The next, the newer models have the T/R on the left side. At least the first helicopters in the vid seems to have a left sided T/R.
The tearing apart ruptures the fuel cells,
No, this armed Mi-17 variants have selfsealing and azotic pressurized fuel tanks. They couldn't have ruptures on the cells due to a few fast rotations and they have no fuel lines in the tailboom. I believe after the disintegrated M/R blades the unbalance broke out the main gearbox and engine struts, rupturing fuel or hydraulic lines in the vicinity of the engines.